source : JAANUS kappa 河童 Lit. river child.
A supernatural water-sprite believed to inhabit Japan's lakes and rivers. The name kappa varies from region to region, and includes kawatarou 河太郎, kawako 河伯, and kawaranbe 河ランベ. The appearance of a kappa also varies, but kappa are generally thought to be about the size of a young boy, and covered with green scales. They also have a snout, bobbed hair, and a saucer-like depression on the top of the head that holds water. When this water supply diminishes, the kappa's special powers diminish. Kappa swim well thanks to webbed feet and hands, but can also walk on land. Kappa also can rotate their arm and leg joints fully. Some kappa resemble otters, turtles with beaks, or have wings. Kappa are said to be fond of cucumbers and of sumou 相撲 wrestling. In some regions kappa are thought to be helpful, but generally their reputation is far more malicious. In particular, kappa delight in abducting humans and horses. Kappa are noted for their aversion to metal objects.
Illustrations of kappa frequently are included in Edo period anthologies of supernatural tales. Kappa are often depicted in comical paintings giga 戯画 in paintings accompanying verse (see haiga 俳画), and occasionally appear in ukiyo-e 浮世絵

- - - - - wikipediaA Kappa (河童, "river-child")
, alternatively called kawatarō (川太郎, "river-boy"), komahiki (“horse puller”), or kawako (川子, "river-child"),
is a yōkai found in Japanese folklore, and also a cryptid. The name is a combination of the word kawa (river) and wappo, an inflection of warabe (child). In Shintō they are considered to be one of many suijin (水神,“water deity”), their yorishiro, or one of their temporary appearances.
A hairy kappa is called a hyōsube (ひょうすべ) Hyosube. There are more than eighty other names associated with the kappa in different regions, including kawappa, gawappa, kōgo, mizushi, mizuchi, enkō, kawaso, suitengu, and dangame.
Along with the oni and the tengu, the kappa is among the best-known yōkai in Japan.
. . . It has been suggested that the kappa legends are based on the Japanese giant salamander or hanzaki 半割 / 半裂 オオサンショウウオ, an aggressive salamander that grabs its prey with its powerful jaws.
. . . shirikodama (尻子玉)- source : wikipedia

Sunny Seki (Author)
The Last Kappa of Old Japan is a warmly written and beautifully illustrated children's book that introduces many aspects of traditional Japanese culture and folklore, while teaching an important lesson about environmentalism.
The story is of a young Japanese farm boy who develops a friendship with a mythical creature— the kappa—a messenger of the god of water. The tale begins in post-Modern Japan when the boy is young and the kappa is healthy and ends when the kappa, now the last one left on Earth, keeps an important promise to his human friend. - source : www.amazon.com